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Purpose: Following short-term all-out exercise, the maximal rate of glycolysis is frequently assessed on the basis of the maximal rate of lactate accumulation in the blood. Since the end of the interval without significant accumulation (t _alac) is 1 of 2 denominators in the calculation employed, accurate determination of this parameter is crucial. Although the very existence and definition of t _alac, as well as the validity of its determination as time-to-peak power (t _Ppeak), remain controversial, this parameter plays a key role in anaerobic diagnostics. Here, we describe a novel approach to determination of t _alac and compare it to the current standard. Methods: Twelve elite track cyclists performed 3 maximal sprints (3, 8, and 12 s) and a high-rate, low-resistance pedaling test on an ergometer with monitoring of crank force and pedaling rate. Before and after each sprint, capillary blood samples were taken for determination of lactate accumulation. Fatigue-free force–velocity and power–velocity profiles were generated. t _alac was determined as t _Ppeak and as the time span up to the first systematic deviation from the force–velocity profile (t _Ff). Results: Accumulation of lactate after the 3-second sprint was significant (0.58 [0.19] mmol L⁻¹; P < .001, d = 1.982). t _Ff was <3 seconds and t _Ppeak was ≥3 seconds during all sprints (P < .001, d = − 2.111). Peak power output was lower than maximal power output (P < .001, d = −0.937). Blood lactate accumulation increased linearly with increasing duration of exercise (R ² ≥ .99) and intercepted the x-axis at ∼t _Ff. Conclusion: Definition of t _alac as t _Ppeak can lead to incorrect conclusions. We propose determination of t _alac based on t _Ff, the end of the fatigue-free state that may reflect the beginning of blood lactate accumulation.

Postexercise heart-rate (HR) recovery (HRR) indices have been associated with running and cycling endurance-exercise performance. The current study was designed (1) to test whether such a relationship also exists in the case of cross-country skiing (XCS) and (2) to determine whether the magnitude of any such relationship is related to the intensity of exercise before obtaining HRR indices. Ten elite male cross-country skiers (mean ± SD; 28.2 ± 5.4 y, 181 ± 8 cm, 77.9 ± 9.4 kg, 69.5 ± 4.3 mL · min⁻¹ · kg⁻¹ maximal oxygen uptake [VO_2max]) performed 2 sessions of roller-skiing on a treadmill: a 2 × 3-km time trial and the same 6-km at an imposed submaximal speed followed by a final 800-m time trial. VO₂ and HR were monitored continuously, while HRR and blood lactate (BLa) were assessed during 2 min immediately after each 6-km and the 800-m time trial. The 6-km time-trial time was largely negatively correlated with VO_2max and BLa. On the contrary, there was no clear correlation between the 800-m time-trial time and VO₂, HR, or BLa. In addition, in no case was any clear correlation between any of the HRR indices and performance time or VO_2max observed. These findings confirm that XCS performance is largely correlated with VO_2max and the ability to tolerate high levels of BLa; however, postexercise HRR showed no clear association with performance. The homogeneity of the group of athletes involved and the contribution of the arms and upper body to the exercise preceding determination of HRR may explain this absence of a relationship.